Device for perforating pipe strings



Sept. 24, 1963 H. EWING 3,104,718

DEVICE FOR PERFORATING PIPE YSTRINGE Filed Aug. 24, 1959 2 Sheets-Sheet 1 Zia-3 IN VEN TOR.

Sept. 24, 1963 EWlNG DEVICE FOR PERFORATING PIPE STRINGE 2 Sheets-Sheet 2 Filed Aug. 24, 1959 IN V EN TOR. .hf m /a BY ATTORNEY United States Patent 3,104,718 DEVICE FGR PERFORATING PIPE SGS Hunter H. Ewing, Whittier, Califi, assignor to Union Oil Company of California, Los Angeles, Calif., a corporation of California Filed Aug. 24, 1959, Ser. No. 835,739 2 (Ilaims. (Qi. 165--24l) The present invention is directed to an improved method and apparatus for completing an oil well in a plurality of productive formations or intervals. More particularly, it concerns a method and apparatus whereby a plurality of subterranean producing intervals may be perforated and produced without the use of concentric tubing strings.

The invention is based on the concept of employing two or more tubing strings extending downwardly through a well bore in side-by-side (as opposed to concentric) relationship, and providing means whereby a gun perforator or equivalent device can be operated within any of said tubing strings without affecting any of the adjacent tubing strings. In number, the tubing strings correspond to the number of productive intervals from which it is desired to produce. Each string extends from the earths surface to the particular interval which it serves and, as stated, the strings are positioned side-by-side in the form of a bundle. In order to permit perforation of each tubing string into the productive interval which it serves without dam-aging adjacent strings, all but the longest of the strings are provided with an alignment section consisting essentially of a relatively short length of tubing of non-circular crosssection. The alignment section of each tubing string is positioned more or less immediately above or below the particular production inteiyal served by that tubing string. Usually each alignment section has an elliptical cross-sectional area, but it may also take the form of a rectangle, triangle, or any other non-circular shape. Most suitably, the shape will be such as to be defined by a relatively long major axis and a relatively short major axis (as in an ellipse or a rectangle), and each alignment section is so oriented on the tubing string that an extension of said major axis fails to intersect any of the adjacent strings in the tubing bundle.

The method and apparatus of the invention are further illustrated and described by reference to the drawings in which:

3,104,718 Patented Sept. 24, 1963 wardly, and the tool is forced into a position with the extended sleeves or pins lying along the elongated of FIGURES 1 and 7 illustrate alternate methods of positioning the assembly of tubing strings with their respective alignment sections in the bore hole;

FIGURES 2, 3 and 4 are cross-sectional views taken at different levels of FIGURE 1;

FIGURES 5 and 6 illustrate the novel aligning tool provided by the invention.

As stated, each alignment section serves to permit perforation of each of the tubing strings individually and without damaging adjacent strings. This is accomplished by providing an aligning tool which is afiixed to the perforating device, e.g., a conventional gun perforator of either the projectile or shaped charge type, and which cooperates with the alignment section to orient the perforating device so that its line of fire does not intersect any adjacent tubing string. According to a preferred embodiment of the invention, the alignment tool comprises an elongated bar fitted on opposite sides with a row of recessed sliding sleeves or pins which are biased in an extruded position by compressive springs. When the tool is inserted in a tubing string of circular cross-section, the sleeves or pins will be in their recessed position compressing the positioning springs, and the tool can move freely in all directions. However, when the tool enters a non circular alignment section the force exerted by the positioning springs extends the sliding sleeves or pins outthe alignment section. The aligning tool and any perforating device alfixed thereto are thus positively oriented with respect to known direction of the elongated axis of the alignment section. For ease of operation, it is preferred to position the alignment section so that an extension of its elongated cross-sectional axis does not intersect any of the adjacent tubing strings. The perforating gun is then fastened to the aligning tool with its line of fire pointed in the same direction as the sliding sleeves or pins of the aligning tool. Thus, when the assembly is in a firing position in the string of tubing, the line of fire will thereby be in the same direction as the elongated crosssecti-onal axis of the alignment conduit, away firom the adjacent tubing strings.

Referring now to FIGURE 1, there is shown a bore hole 8 traversing productive intervals A, B, C and D. A tubing string assembly consisting of tubing strings 10, 11, 12 and .13, held together in a bundle by brackets or clamps '14, 15, 16 and 17, extends downwardly within well bore 8. The shortest tubing string it extends to a depth somewhat below that of the uppermost productive interval A, and is fitted at its lower end with an elliptical alignment section 20. The next longwt tubing string 11 similarly extends to the subjacent interval B, and is similarly fitted with an alignment section 21, to interval C, and comprises alignment section 2.2. The longest tubing string 13 extends to the lowest interval D. Since tubing string 13 and interval D can be perforated without danger of damaging any other tubing string, there is no need to provide string 13 with an alignment section. The alignment section 20 used to align a perforating device within tubing string 10 at productive interval A is shown in cross-sectional view in FIGURE 2. Alignment sections 21 and 22 are similarly positioned in tubing strings l1 and 12, respectively, and are similarly shown in FIGURES 3 and 4, respectively. Alignment sections 20, 2.1 and 22 may be any length. However, it is pre-. ferred that they be approximately twice as long as the aligning tool, e.g., 10 or more feet. The minimum diameter of these conduits should be approximately the same as that of the standard tubing sections employed in the, string, and the elongated diameter should be about 1.3 or more times as great as the minimum diemeter. Tapered reducers of gradual increasing cross-section are preferably employed between the circular conduit of the tubing string and the alignment sections to facilitate removal of the aligning tool from the alignment section.

In the particular arrangement shown in FIGURE 1, the well bore has been completed into the productive zone without a casing. In effecting this type of completion, the bore is drilled in the conventional manner and the location of the productive intervals is determined by suitable surveying and/ or logging methods. If necessary, the bore may be cased in for (at least part of the way down to the production zone. The tubing assembly is then run into the bore and is supported therein by conventional tubing hangers while the bore is filled with cement to a level which is usually, but not necessarily, above that of the production zones. In FIGURE 1, the mass of cement filling bore hole 8 is shown at 23. When it is desired to complete the well into the individual productive intervals, the aligning tool provided by the invention is coupled to a suitable perforating device and the assembly is run into the tubing string which serves the particular interval to H be perforated. When the alignment section is positioned Tubing string 12 extends" tool will be described. in FIGURE 5 the tool 30 is shown with its upper end threaded into a spacer rod 37 which in turn is threaded into a gun p'erforator 38. The perforator is supported by another spacer rod 44 which in turn is suspended by a wire line 42 containing the electrical conductor [for firing the perforator. The tool and gun assembly is shown in firing position within tubing string and its cooperating alignment conduit 20.

The aligning tool itself consists of a body member 30, suitably taking the {form of a round bar approximately 5 feet or more in length. A central bore 31 extends the length of the bar 30 to carry an electrical conductor cable when the perforator is positioned below the aligning tool. Along the length of the bar at right angles to its longitudinal axis, holes 32 are drilled to receive sliding sleeves 33. The latter are biased outwardly by compression springs 36 which are illustrated in FIGURE 6 in their fully expanded state. Accidental discharge of sleeves 33 from their holes 32 can be prevented by employing snugly fitting sleeves. Sleeves 33 are constricted at their outboard ends so as to hold a ball bearing 34- within each sleeve. A compression spring 35, positioned between the inboard end of each of sleeves 33 and the bearing 34, forces the latter against the crimped edge 65 of the sleeve. Spring 35 is chosen so as to provide a greater resistance to compression than spning 36. The weight of the tool and the force of the compressive springs are selected so as to prevent the tool from becoming hung up in recesses in the tubing such as normally encountered at the tubing joints. When the tool reaches such a joint, the sleeves will, of course, be forced into the recess by the compressive springs. The weight of the tool, however, is sutfi icnt to cause bearings 34 to roll out of the recess, retracting the sleeves. As will be apparent to those skilled in the art, various other techniques can also be employed for this purpose.

- FIGURE 6 illustrates the position of the aligning tool within elliptical-shaped alignment section shown in tubing string 1%) of FIGURE 1. Compression. springs 35 and 36 are extended, and the sleeves 33 are at their extended position, insuring that they lie along the elongated axis of the conduit 29. The aligning tool is sized so that it will fit within the tubing strings when sliding sleeves 33 are in their recessed position. Upon entering an ellipticalshaped alignment section, the aligning tool is rotated slowly so that it will pass through the alignment which has the extended sleeves 33 lying along the elongated axis of the conduit by working the tool up and down within the elliptical-shaped alignment section. When so moved, the compressive force exerted by springs 35 and 36 will rotate the aligning tool into the position shown in FIG- URE 6. The lower end of the aligning tool is threaded to fit a perforating gun, rope socket, spacer bar, bull plug or sinker bar, etc.

In use, the perforating device is rigidly positioned on the aligning tool in such manner that it fires in a direction which is fixed with respect to the orientation of the aligning tool. Usually, it is most convenient to orient the perforate-r as shown in FlGURES S and 6, i.e., so that the charges 39 of perforator 38 fire in a direction parallel to the sleeves of the aligning tool and hence parallel to the elongated axis of the alignment section. Each of the latter is oriented on the tubing string as shown in FIGURES 24 to provide an area of fire indicated by lines E and F which is not intersected by an adjacent tubing string. The assembly is then supported by a wire line and is lowered into one of the tubing strings. When the aligning tool reaches the alignment section, it is worked up and down to permit the springs 35 and 36 to work the tool into alignment along the elongated axis of the alignment section. At this time, the perforating gun is in position so that it can be fired through the mass of concrete (23 in FIGURE 1) and into the productive interval without danger of perforating the adjacent tubing strings.

Referring now to FIGURE 7, a modification of the invention is shown wherein a well casing extends throughout the length of the production intervals. bly of tubing strings is held in place by packers 45, 46, 47 and 48, positioned above and isolating each productive interval. Tubing string 5i), carrying alignment section 60, is the shortest, and communicates with uppermost production interval A. Tubing string 51 communicates with subjaoent interval B and carries alignment section 61. Tubing string 52 communicates with production level C below level B and carries alignment section 62. Tubing string 53 is the longest and communicates with production level D. There is no need to use the aligning tool and expanded diameter conduit with tubing string53 since there are no adjacent tubing strings within production level I). Packers s5, 46, 47 and 48, of conventional design such as those illustrated and described on page 894 of The Composite Catalog of Oil Field Equipment and Services, 24th Edition, volume 1, hold the tubing assembly in place in the casing, and prevent the alignment conduits from twisting out of position.

The operations of perforating and aligning the gun perforator with respect to the embodiment shown in FIG- URE 7 are the same as discussed with the embodiment of FIGURE 1.

The nature and objects of my invention having been completely illustrated and described, I hereby claim:

1. An aligning tool for use in wells comprising an elongated body element having at least two rows of spaced holes, each of said rows disposed on opposite sides. thereof and positioned at right angles to the longitudinal axis 7 thereof, sleeves carried within said holes and adapted to slide therein, means for biasing said sleeves radially outwardly, a ball bearing rotatably mounted at the outboard end of each of said sleeves and extending beyond the same, means for retaining said ball bearings within said sleeves, and means biasing said ball bearings radially out wardly.

2. An apparatus for completing a Well at a plurality of production levels comprising a plurality of conduits within said well, each of said conduits being of a different length than the other of said conduits to correspond to the production level which it serves, all but the longest of said conduits being provided at a level adjacent its corresponding production level with a reducer section having an upper end of a circular cross-section conforming to and i attached to said conduit and a lower end having a noncircular cross-section with a major axis and a minor axis, said ma or axis being greater than the diameter of said conduit, said lower end of said reducer attached to a short alignment conduit with a cross-section conforming to said non-circular cross-section of said reducer, said reducer and alignment conduit attached to said conduit so that the extension of said major axis of said non-circular cross-section does not intersect any of the adjacent conduits, an alignment tool within said alignment conduit, said alignment tool comprising an elongated body element of lesser length than said alignment conduit and having two rows of spaced holes, each of said rows disposed on opposite sides thereof and positioned at right angles to the longitudinal axis thereof, sleeves carried within said holes and adapted to slide therein, means for biasing said sleeves radially outwardly, a ball bearing rotatably mounted at the outboard end of each of said sleeves and extending beyond the same, means for retaining said ball bearings within said sleeves, and means biasing said ball bearings radially outwardly, said alignment tool supported within said alignment conduit so thata vertical plane through said two rows of said sleeves is directed along said major axis of said non-circular cross-section, a second elongated body element attached to said alignment tool, said second body having two rows of explosive changes, each of said roWs disposed on opposite sides thereof and positioned at right angles to the longitudinal axis thereof, said second body being attached to said first body so that its two rows of explosive charges also lie in The assern-.

the said vertical plane, cable means supporting the assembly of said first and second bodies, and ignition means to ignite said explosive charges.

References Cited in the file of this patent UNITED STATES PATENTS 2,134,287 Matlock Oct. 25, 1938 2,400,678 Archie May 21, 1946 2,408,419 Foster Oct. 1, 1946 6 Russell Apr. 6, 1948 D011 July 12, 1949 Smith Apr. 4, 1950 Krosnow et a1. Mar. 17, 1953 Bielstein Feb. 12, 1957 True Mar. 19, 1957 Bielstein June 23, 1959 Dafiin Feb. 2, 1960 Tausch et a1 May 31, 1960 

1. AN ALIGNING TOOL FOR USE IN WELLS COMPRISING AN ELONGATED BODY ELEMENT HAVING AT LEAST TWO ROWS OF SAPCED HOLES, EACH OF SAID ROWS DISPOSED ON OPPOSITE SIDES THEREOF AND POSITIONED AT RIGHT ANGLES TO THE LONGITUDINAL AXIS THEREOF, SLEEVES CARRIED WITHIN SAID HOLES AND ADAPTED TO SLIDE THEREIN, MEANS FOR BIASING SAID SLEEVES RADIALLY OUTWARDLY, A BALL BEARING ROTATABLY MOUNTED AT THE OUTBOARD END OF EACH OF SAID SLEEVES AND EXTENDING BEYOND THE SAME, MEANS FOR RETAINING SAID BALL BEARINGS WITHIN SAID SLEEVES, AND MEANS BIASING SAID BALL BEARINGS RADIALLY OUTWARDLY. 